Cell mechanical properties, including intracellular viscosity, play a critical role in cell function, differentiation, and disease. Altered gravity is known to affect cell behavior, yet its impact on intracellular viscosity remains poorly understood. This study investigates whether hypergravity modifies the viscosity of Hela cells using Single Particle Tracking (SPT) of endogenous particles in the Large Diameter Centrifuge at ESA ESTEC. Particle trajectories were analyzed to calculate Mean Square Displacement and diffusion coefficients, allowing estimation of intracellular viscosity via the Stokes-Einstein equation. The SPT software successfully measured viscosity changes, suggesting potential alterations under hypergravity. While promising, further research is needed to confirm whether observed changes are solely due to hypergravity, including testing additional cell types, controlling environmental variables, and examining cytoskeletal contributions. ... Read more